1. Field of the Invention
The present invention relates to a compressor and more particularly, to a hermetic reciprocating compressor for compressing and discharging refrigerant in a refrigerator or an air conditioner, etc.
2. Description of the Prior Art
Generally, as shown in FIG. 1, a conventional hermetic reciprocating compressor includes a sealed casing 10, an motor portion 20, a compression device portion 30, an elastic supporting portion 40, and a crankshaft stopper 50.
The sealed casing 10 includes upper and lower shells 11 and 12, respectively, which are substantially hemispheric in shape. The sealed casing 10 accommodates the motor portion 20, compression device portion 30, elastic supporting portion 40, and the crankshaft stopper 50.
The motor portion 20 includes a stator 21, rotor 22, and crankshaft 23. The crankshaft 23 is press-fit to the rotor 22 and includes an eccentric portion 23a formed on one side thereof
The compression device portion 30 includes a cylinder block 31 having a compressing chamber 31a, a piston 32 reciprocally movable within the compressing chamber 31a of the cylinder block 31, and a connecting rod 33 disposed between the piston 32 and the eccentric portion 23a of the crankshaft 23 to transform and transmit the rotary movement of the crankshaft 23 into a linear reciprocal movement of the piston 32.
The elastic supporting portion 40 absorbs and damps various vibrations generated during operation of the compressor by elastically supporting the cylinder block 31 of the compression device portion 30 toward the lower shell 12 of the sealed casing 10. Such an elastic supporting portion 40 includes a plurality of snubbers 41 arranged on the bottom surface of the lower shell 12, a plurality of protrusions 42 protruding from the lower portion of the cylinder block 31, and a plurality of suspension springs 43 disposed between the snubbers 41 and the protrusions 42 for elastically supporting the cylinder block 31.
The motor portion 20 and the compression device portion 30 can move vertically and horizontally during conveyance of the compressor into contact with the inner wall of the sealed casing 10. The crankshaft stopper 50 restricts the movement of the motor portion 20 and the compression device portion 30, both of which are elastically and movably supported in the sealed casing 10 by the elastic supporting portion 40. The crankshaft stopper 50 is welded onto the inner upper side of the upper shell 11 and includes a movement restricting hole 51, into which an upper end of the crankshaft 23 is inserted. Since the upper end of the crankshaft 23 is received and supported in the movement restricting hole 51 of the crankshaft stopper 50, movement of the motor portion 20 and the compression device portion 30 is limited. Accordingly, possible deformation and breakage of compressor components by contact with the inner wall of the sealed casing 10 during wide horizontal and vertical movements of the electronic device portion 20 and the compression device portion 30 during the operation of the compressor are, prevented.
In the conventional hermetic reciprocating compressor such as that described above when electricity is supplied, rotary movement of the crankshaft 23 is transformed and transmitted into linear reciprocal movement of the piston 32 through the connecting rod 33. The piston 32 linearly reciprocates within the compressing chamber 31a of the cylinder block 31 to compress and discharge a refrigerant. The high-speed refrigerant flow and vibrations from various parts of the motor portion 20 and the compression device portion 30 inevitably produce noise. The suction and discharge mufflers 13 and 14 reduce the noise from the refrigerant flow, while the elastic supporting portion 40 absorbs and damps the vibrational noise.
In the conventional hermetic reciprocating compressor, however, the suction muffler 13, discharge muffler 14, and the elastic supporting portion 40 only reduce the noise produced during the operation of the compressor to a certain extent. The noise of the compressor remains high due to lack of structure for reducing transmission noise that is caused from the resonance of the sealed casing 10.
The present invention has been made to overcome the above-mentioned problems of the prior art, and accordingly, it is an object of the present invention to provide a hermetic reciprocating compressor for reducing the noise level of the compressor by reducing transmission noise caused by resonance of a sealed casing.
Another object of the present invention is to provide a hermetic reciprocating compressor capable of reducing the transmission noise caused by resonance of the sealed casing by making simple changes to the existing structure without changing the design of the compressor itself.
The above objects are accomplished by a hermetic reciprocating compressor according to the present invention having a resonance reducer portion integrally formed on the crankshaft stopper which is attached to the upper inner portion of the sealed casing. The resonance reducer portion of the crankshaft stopper restricts movement of motor portion and the compression device portion to increase the rigidity of the sealed casing and reduce the resonance of the sealed casing.
According to the present invention, the vibration, which is produced during the operation of the compressor and is transmitted to the sealed casing, is absorbed or damped by the resonance reducer portion of the crankshaft stopper, thereby reducing and/or preventing resonance of the sealed casing. Accordingly, transmission noise due to resonance of the sealed casing can also be reduced.
According to the preferred embodiment of the present invention, the crankshaft stopper includes a centrally formed movement restriction hole. The movement restriction hole receives the upper end of the crankshaft, the resonance reducer portion vertically bent and formed around the movement restriction hole, and at least two welding portions for connecting the crankshaft stopper.
There may be either two or four welding portions that extend vertically upward and radially outward from the movement restriction hole. Each welding portion has a plurality of embossings formed thereon.
Further, it is preferable that the crankshaft stopper with the integrally formed resonance reducer portion be attached to the upper shell of the sealed casing at an offset angle approximately of 45xc2x0 from the reciprocal movement path of the piston of the compression device portion.